1. Field of the Invention
The present invention relates to an article detection device and a method for detecting the article, more particularly, it relates to an article detection device used with a bar code reader.
2. Description of the Related Art
Recently, bar code readers are widely utilized for management of goods in a POS (Point Of Sales) system. In general, there are two types of bar code readers, i.e., an installed type and a handheld type. The former is large and installed in a counter of a large store. This type has a plurality of scanning beams (laser beams) to be irradiated onto a bar code symbol so that it is possible to provide highly precise detection of the bar code symbol regardless of a direction of entry of the article into a scanning area of the laser beam. Further, in general, this type has an article detection device for detecting the entry of the article into the scanning area of the laser beam before the laser beam is activated. Since the laser beam is activated after detection of the article, it is possible to extend the life of a laser beam source.
In general use, the operator sits next to a bar code reader. However, the light reflected from the operator should not be detected as an article by the article detection device. Further, random external light (ambient light), for example, fluorescent lamps and sunlight, exists around the article, and the light reflected from the operator and the ambient light have an undesirable influence on the detection of the bar code symbol.
Accordingly, it is necessary to eliminate the influence of this reflected light to increase the precision of the detection of the bar code symbol.